Process and apparatus for recovering copper from its oxidized or roasted ore



Aug. 18, 1925. l 1,550,521

J. B. DU FAUR PRocEss AND APPARATUS FOR REcovERING corran FRou 1Ts-=oxIDIzED 0R RoAsTED ons y Filed Sept. 28, 1925 PRESSURE ULFHUR DIXIDE GHS NDH/RONDE?? Patented Aug. 18,

l Dmuri-:n STATES PATENT oFlcE.

JoHN BEBTEA'H DU Baumer TUBBAHUBBA, NEAR SYDNEY, NEW soUTH WALES, AUSTRALIA., AssIeNoB. To ALBERT :mns HCBBIBE ANnBHILIB ALBERT xcBBILE, BoTH orv ADELAIDB, soUTH BBocEss-ANB ArraBaTus roB.

AUSTRALIA, AUSTRALIA.

BEcovEBING comme Bisou ITs oxInIzEn 0B. BoAsTEnoBE.

` application nieu september as, 192s. serial No. 665,395. i

`To aZZfw'zom it may concern;

Be it Iknown that I, JOHN BERTRM DU FAUB, a subject of the King of Great Britain and Ireland, residing at Turramurra, near Sydney, State of New South Wales, Commonwealth of Australia, have invented a cer-- tain new and useful Process and Ap aratus for Recovering Coppel; from Lts Oxi ized or .Roasted Ore,V ofy which the following is a 1,0 "specification, l

This invention has been devised for the recovery of copper from its oxidized or roasted ore and especially from those -in which it exists in the form of carbonate or 1.5 silicate or both.

*My improved process consists essentially in. treating the ore whether in the form of sands or slimes with a leaching solution which contains sulphate of iron and which 'is continuously impregnated with a current of sulphur dioxide gas and air 4under pressure which is'injected into the solution in such manner as to cause vit to circulate through the ore. VIf the ore is in the form of sands it is placed in a vat having a false bottom and therein subjected to the action of a leaching solution containing sulphate of iron, such solution being caused to circulate through two pipe systems, inv the one of which the solution is drawn from beneath the false bottom and discharged over the f on the air lift princ1ple, and in the otherY system solution is drawn from beneath its surface in the vat and discharged over its surface being caused to circulate by means of a current of air under pressure injected into the pipe at a suitable point and functioning ron the air lift principle also.v When the ore is in the form of slimes I use in place of the leaching vat/'any well known form of agitator vat sometimes known as an agitator.

A convenient form of apparatus for carrying out this process when the ore is in the form of sands is shown in the accompanying 5 drawing, which is an elevation partly in section.

, A. is a leaching vat of any ordinary con-y struction havingI a false bottom B preferably formed of loosely set brick-sor wood planks Y bored with a number of holes,I and covered with suitable lilteing ,material such as gravel or cocoanut matting asis generally lus`ed 'in leaching vats.

C 1s a U shaped pipe the one end of which passes; through the wall of the vat A and opens into thespace beneath the false bottom B. Its one leg (the inlet) is carried downward below the'bottom of the vat `in a pit or `shaft D and'then by` means of a return bend 1ts other leg (tle outlet) is carried up` and 'thence to and over the top of thevat as shown. To the rising leg ofthe pipe C, a short distance above the return bend, is connected a` pipe yE whereby a mixtureof sulphur dioxide asand air under pressure may be forced-into the pipe C by means of a- `suitableblower (not. shown) of ordinary ever. may bejust levelwith the surface of the solution or even below it. `Within the `pipe F is asmaller pipe I-Iwhereby compressed air may be delivered to the pipe F a short distance abovge its lowest part by means of a suitable blower (not shown) of ordinary'` construction.

My process 1s carried out as follows- The oxidized or roasted ore, which has` been previously crushed to the desired degree of ineness, is placed in the vat A upon the vfalse bottom B. It is then covered with the leaching solution containing sul hate of iron, which has been previously pr uced in any well knownl manner, but subsequently additional sulphate may be formed by absorption of soluble iron from .the ore under treatment. The leaching solution passes through the ore and through the false bottom and fills the pipe C up to its in thevat.

A mixture under pressure of sulphur dioxide gas and air is then forced through the own level pipe E into the pipe C and the action of the false bottom B) andfdischarged over the sur' face of the ore, through which it again percolates to the pipe C. The sulphur dioxide is preparedpreferably by burning sulphur or pyritic ores in an enclosed furnace through which the compressed air is forced by the blower, or it may be prepared by y drawing the gases from any suitable furnace ore is governed according to (l) the po-f' of aeratingk the solution.

'working at atmospheric pressure through.

any suitable form of compressor to gain the necessary pressure before use.Y

The rate of circulation for each batch o rosity of the ore bed (2) the rate at which the ore bed is able -to neutralize the leaching properties ofthe solutions. l

u By this means the copper inthe ore is brought into solution and a high absorption \0f the sulphundioxide bythe solution 1s ob- Y. The circulation system-through the pipes v F and H when properly regulated ensures erator.A The iron content in the ferrie state of the leaching solution may also be varied the conversion of the 'dissolvedcopper' into ,sulphate of copper. It also ymakes it possible,l in conjunctionk with the main leaching solution circulating system through the pipes C and E, by varyingithe'relative rate of circulation through the two circulating systems, to vary the 1ron contents'o'f the solution at will; thatis, the iron contents of the solution may be completely precipitated and again redissolved at the will of the opby this means. l Y .v

When the ore is in the form of slimes,` in.

place oftheleaching vat shown, I use an agitator vat of any well known type, preferably one equipped with an air lift pump,

, the drawing, the inlet pipe/opening tothe lower part of the agitator and the outlet discharging over the surface 'ofthe solution` in the vat. The slimes are/treated as i'n the case of the sands by a leaching solution whlch contains sulphate of iron and 'whichis continuously impregnated with a current orA sulphurk dioxide gas and air under pressure.`v .f w l. l

From time to time portions of the solutionare withdrawn from the vat, and thev dissolved copper is preci itatedfrom the' 'solution by means of meta 'c iron and iron is dissolved as sulphate of iron as in the well known cementation process. This sulphate of iron solution is the source of supply of thesulphate of iron necessary to the Y process, when insuilicient soluble iron sulphate exists in the ore. Only a small amount ofV sulphatefof iron in solution is necessary as it is not consumed in the process, its action being more or less catalytic. From 1% to 1/270 is generally used but either Ymore or lessrcould be used.

If the leaching vatbe too large for-one i circulating apparatus as above described, several may be ittedto it.

Care must be taken that as far as possible the several parts of the apparatus are madeY of material that will not be destroyed by the solutions passing through them.

1. A process for the recovery of copper from oxidized or roasted ore consisting in treating the ore with a leaching solution which contains sulphate of ironand subject ing Vthe leaching solution to the action of a mixture o f sulphur dioxide gas `and air.

2. A process for the recovery of c opper from oxidized vor roasted ore, conslsting m action of a leaching solution containing sulf phate of iron, causing a mixture of sulphur dioxide gas and air 'to' circulate through the leaching solution, and in causing the circulation of the leaching solution in the vat. Y

4. A process for the recovery of copper from oxidized or roasted ore consisting in placingy the ore in a vat above the bottom of the same, subjecting the ore to the action of a leaching solution containing sulphate of iron, withdrawing the leaching solution from the bottom of the vat and discharging it along'with a mixture of sulphur dioxide gas and lair onto the vsurface of the said solution, and subjecting the solution to a.' current of air under pressure whereby to cause a portion ofthe solution to be raised and delivered upon the surface thereof.

5. An apparatus for use in the recovery prising the combination with' a leaching vat los of copper-from oxidized or roasted ore', comof any suitable well known type, of a circulating pipe system operating on the air. lift princlple and comprismga main Ulshaped 'pipe and a smaller pi e connecting ltherewith and adapted to e' connected with a blower, the main pipe ,openinginto the vat' at the point Ynear its bottom' and passing thence below the bottom of the vat and thence upward and over the top of the vat, and the smaller pipe being connected to the Amain pipe near the bottom ofthe upwardly rising leg of same, substantially as described' and for the purpose set forth.

6. An apparatus for use in the recovery of copper from oxidized or roasted ores containing same, comprising the combinaf' tion with a leaching vat of any suitable well known type, of two circulating pipe systems operating on the air lift principle; one piper* system comprising a main U-'shaped plpe and a smaller pipe connecting therewith and i adapted to be connectedl with a main pipe opening into the vat at a point near its bottomV passing thence downward below t-he bottom of the vat thence upward and over the top of the vat, and the smaller pipev being connected to the main pipe near the` positioned approximately level with the surface of the solution, and the smaller pipe being positioned Within the larger pipe and adapted to deliver air thereto ashort distance above its lowest part, substantially as described and for the purpose set forth.

7. An' apparatus for recovery of copper from oxidized or roasted ores, comprising a vat having a perforated false bottom, a U-shaped pipe extending below the vat and having one leg opening into the vat below the false bottom and its other leg extending above and over the vat, a small gas and air pipe connected to the lower part of this leg extending over the vat, a U-shaped pipe in the vat yand having legs of unequal length, the longer leg being adapted to extend above the solution and the shorter one to be below the level of the solution of the tank, and an air pipe extending into the longer leg of said pipe.

In testimon that I claim the foregoing as my inventionI I have signed my name this 7th day ofsAugust, 1923.

JOHN BER-TEAM DU FAUR. 

